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Figure 3 | SpringerPlus

Figure 3

From: Mean-field analysis of orientation selectivity in inhibition-dominated networks of spiking neurons

Figure 3

Orientation selectivity across the population. (A) Distribution of a global measure of orientation selectivity, OSI=1−Circular Variance (Ringach et al. 2002), in the network. Lighter colors show the distributions for lower contrasts, respectively. All inputs have an OSI of 0.05. (B) Distribution of an alternative measure of orientation selectivity often used by experimentalists (Niell and Stryker 2008). OSI* is the difference of activity at preferred and orthogonal orientations, normalized by their sum, (rprefrorth)/(rpref + rorth). (rpref and rorth) are obtained from the best fit of a cosine function to output tuning curves, evaluated at Output PO and Output PO+90°, respectively. Alternatively, OSI* can be computed from a linear interpolation of data points (inset). Lighter colors show the distributions for lower contrasts, respectively. All inputs have an OSI* of 0.1. (C) The OSI of all neurons for medium contrast (MC) vs. low contrast (LC), and for high contrast (HC) vs. medium contrast are plotted in the left and right panels, respectively. The diagonal line indicates a perfect contrast invariance of OSI. (D) Output PO vs. Output OSI for all neurons in the presynaptic pool of the neuron shown in Figure 2A. A stimulus of medium contrast has been applied. The neuron receives input from presynaptic neurons that are themselves highly selective on average (OSI distribution on the right), and which uniformly cover the whole range of possible Output POs (distribution on top). The Output OSI and Output PO of the target neuron are 0.65 and 105°, respectively. Other neurons receive similarly heterogeneous inputs (not shown).

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